also...don't head out with a tail wind. You'll get a better workout and feel a lot better if you head out into a head wind and then come back with that tail wind. I also learned this the hard way, or well I made my friend learn it the hard way when I trying to get him back into the sport accidentally went out with a tail wind, he died on the way back, of course he also drank poorly and who knows what his nutrition was like the previous day.